buying a 92 Corvette project car.
Want to put some heads/came etc... into it, but am a bit out of the fold re: LT-1 info. Most of my experience has been LSx related past few years and have fogotten much of what I learned re: LT series motors.

I seem to recall the stock rod bolts were the weak link in these motors
I want about 375-400rwhp from the Y body.
I also seem to recall a max safe rpm of 6200 rpm's on the stock bottom end which will really limit me in cam choices and probably won't hit my HP goals.

Please advise
I did search but came away just as confused as before
thx
John

 

I would agree with 6200 rpm being the upper limit on the stock bottom end. The biggest issue IMO is the bearings start to come apart after repeated 6200+ rpm use.

 

i don't think there is one set RPM that you must not cross. If you want it to last 100k don't spin it over the stock redline, personally i spin my 197k shortblock to 6800 on a cc 306 but i don't expect it to last forever and am planing on a rebuild sooner than later. BTW, i'll post pics when mine lets go, it should be good, hahaha

 

My understanding is if a motor has seen 5800 RPM max for tens or even hundreds of thousands of miles then it becomes acclimated to those RPM's and a "sweet spot" is developed.

Once you start revving that engine much higher you are no longer in that "sweet spot". The heat, friction and natural forces plus current wear takes its toll on the bearings and rod bolts etc. Based on this I think its safe to say that a brand new LT1 straight off the showroom floor could be hopped up and it would easily survive much higher RPM's right off the bat.

Raising the RPM's on an existing engine is a roll of the dice but the consensus seems to be 6200 RPM max.

 

huh, i guess i have never heard that logic before but it could be true. At any rate if you start caming an existing engine there is always a chance to spin a bearing due to a dirty install.

 

This was explained to me by Lloyd Elliot.

 

Rod bolts are a weak link.
Ya will be limited in RPM's to what the computer is programed for. In LT1 Camaro it's 7/7200 and the fuel tables run out.
Ya can get an aftermarket system and the sky is the limit.
Your cam will determine the shift points.

 

I once asked about good cams for stock rev ranges (below 6200), and the two that came up were:

Ligenfelter 74211. 211/219, .530/.560 with 1.6's 112 LSA

Crane 104227 ("227")... 210/224, .511/.553 with 1.6s. 112 LSA

Notice the short duration and very high lift. These may not have the peak HP of many other cams, but the "area under the curve" is quite impressive. I seem to recall guys running easy 12s with the Crane.

 

For me I thought the small Joe O. cam would see a little less RPM. But the set-up dictates a 6400 rpm shift point for the best 1/4 mile times. It really doesn't bother me though, as the stock short block only has 29k on it. Plus if it lets go I'd like to build a econo 383 that can hold up to a 150 shot of nitrous.